title: The association of MMP-9 and IL-18 gene promoter polymorphisms with gingivitis in adolescents.
abstract: OBJECTIVE
  Interleukin 18 (IL-18) is shown to be a proinflammatory cytokine that regulates the expression of matrix metalloproteinase 9 (MMP-9). The aim of this study was to test for differences between Czech adolescents with and without gingivitis in relation to MMP-9 and IL-18 polymorphisms.
  
  
  METHODS
  A total of 298 Caucasian children, aged 11-13 years, were examined to assess gingival health. DNA for genetic analysis was obtained from buccal epithelial cells, and the MMP-9 -1562C/T and IL-18 -607A/C variants were identified with PCR-RFLP.
  
  
  RESULTS
  Gingivitis was present in 49.3% of the adolescents examined, the rest of the group was considered healthy. The IL-18 -607C and MMP-9 -1562T alleles were found in 58.9% and 8.3% of the healthy subjects, and in 62.2% and 15.0% of the patients with gingivitis, respectively. Although differences in allele frequencies were not significant for IL-18 variant, they were significant for MMP-9 polymorphism (p=0.01, p(corr) < 0.05). Furthermore, a highly significant association of the composite genotype (formed by the variants of the both genes) with gingivitis was found (p=0.004, p(corr) < 0.05).
  
  
  CONCLUSIONS
  The -1562 T allele of MMP-9 gene could have a role in gingivitis in adolescents. In addition, interaction of the MMP-9 and IL-18 genes could be considered a risk factor for the development of gingivitis in children.
authors.affiliation: Faculty of Medicine, Masaryk University Brno, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Vokurka
authors.forename: Lucie
authors.initials: L
authors.lastname: Klapusová
authors.forename: Pavla
authors.initials: P
authors.lastname: Pantuckova
authors.forename: Martina
authors.initials: M
authors.lastname: Kukletova
authors.forename: Lubomír
authors.initials: L
authors.lastname: Kukla
authors.forename: Lydie Izakovicova
authors.initials: LI
authors.lastname: Holla
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D005891:Gingivitis / Q000235:genetics*; D006801:Humans; D020382:Interleukin-18 / Q000235:genetics*; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D011401:Promoter Regions, Genetic
chemical_list: D020382:Interleukin-18; D020780:Matrix Metalloproteinase 9